1. Field of the Invention
This invention relates to a fibrous nonwoven medium for growing plants from seeds. More particularly, the invention concerns such a medium which comprises a layer of hollow fibers of synthetic organic polymer. The medium, especially when its hollow fibers contain water-soluble adjuvants, can support, enhance and protect plant growth.
2. Description of the Prior Art
Non-woven mats or sheets composed of synthetic or natural fibers are known for growing plants directly over soil or in soil-less systems (such as hydroponic systems). U.S. Pat. No. 2,923,093 (Allen) discloses a seed-planting mat comprising multiple fibrous layers; one layer contains seeds; and all layers are needled together. U.S. Pat. No. 3,557,491 (Franklin et al) describes a nonwoven polyolefin sheet having a surface layer which contains seeds and is made of a water-soluble material or a gum containing a fertilizer. British Patent 1,367,090 discloses a seed-containing, rot-resistant fiber web for planting and reinforcing ground areas. U.S. Pat. No. 4,066,490(Yoshimi) discloses a process and apparatus for making a lawn nursery strip which comprises sowing seeds on a strip of carded regenerated cellulose fibers, spraying a liquid fertilizer over the seeded surface, applying a liquid binder and finally press-bonding a net-like nonwoven material onto the surface. U.S. Pat. No. 4,357,780 (Ball) discloses spraying a soluble adhesive onto a mat of randomly oriented, unmodified, natural, straw-like cellulosic fibers and then depositing seeds and a water-soluble fertilizer thereon. Various other types of seed-bearing, plant-growing mats are disclosed in US. Pat. Nos. 2,976,646 (Hansen et al), 3,914,901 (Muldner), 4,318,248 (Muldner) and 4,363,197 (Baron).
Although the mats described in the above-cited patents can be used for growing plants, a fertilizer usually is sprayed onto the mat surface to provide plant nutrients. A mat with fertilizer on its surface usually requires special care in handling to avoid potential skin-irritation problems. Also, such surface-applied materials often are readily washed away by rain storms, which in turn, can lead to problems of soil and ground-water contamination. For best growth, plants need to be fed nutrients slowly.
A purpose of the present invention is to provide a seed and plant-growing fibrous medium that can alleviate the shortcomings of the known plant-growing media and can provide slowly releasable, water-soluble plant adjuvants.